Fast way of creating lots of 25mm holes in plywood

[ajayre]

I have 12mm plywood and I need to create a lot of 25mm holes in it. For previous parts like this I used a hand-held drill and a Forstner bit, but it is slow going. I have to cool down the bit regularly and I have to drill each hole from both sides to avoid splitting the veneer. It's hard on the drill batteries which I have to keep swapping.

Is there a better way to quickly and easily create these holes?

My only thought is a template with a plunge router and a a spiral bit, but it will be tedious repeately clamping and removing the template.

Thanks, Andy

 

[bp122]

If you get a CNC or a 3d printed template made with a grid of holes (9 or 16), that might save you some clamping time with the router

Hole saws don't give a good finish or are very accurate.

To help with your router work, you could mark out the holes first, use a 15 or 20mm auger bit to take out the bulk of the hole center and then use your template to enlarge the hole with a router and a 1/2 inch bearing guided bit or a straight bit with a guide bush (doesn't even need to be spiral)

This will be quicker than just routing out from scratch, you don't need to change the depth at all, reduce router dust and noise.

 

[bp122]

If you are getting a 3d printed template made, also get a like a custom bench dog so that it will help you align the template to previous holes after the initial row of holes.

 

[Bingy man]

Any method you choose will be tedious as you can only drill 1 hole at a time , only thing I’d recommend is using a back board of 18mm old ply or mdf and drill straight through with a sharp bit of. Depending on how accurate you need them dictates what you use - drill , router etc .

 

[fleyh]

I would create a template with, for example, a 9x9 grid of holes (these can be made with a drill).
I would then create a couple of dowels or dogs to anchor the template to the already-drilled holes, and use that template with a router, either with a profile cutter or a bushing.

Obviously, the template holes would need to account for the bushing if this option is used. With a profile cutter, this is not an issue, and the holes should be the exact/final diameter.

My process would be as follows:

• Align the template.
• Use a standard hand drill with a regular bit (not a Forstner bit) to create an initial hole, so the router bit can drop into it.
• Drill as many holes as the template allows.
• Switch to the router and expand the hole sizes to the final diameter.

If the router cutter is capable of drilling through (it must have an appropriate point for this), the hand drill step is unnecessary.

 

[ajayre]

Thanks for the great ideas! Much appreciated. Andy